The invention relates to a yarn storage and supply apparatus, particularly for textile machines, having a storage drum in the manner of a cage with rods, which has a number of elongated yarn support elements, distributed uniformly at equal radial distances from the drum shaft and in the circumferential direction, which extend substantially in the direction of th drum shaft and are secured at both ends on a drum body or part connected with it and each element is embodied in the form of a narrow yoke.
It has been proposed to construct the yokes with regions tapering radially inward and acting as a run-on incline for the oncoming yarn and adjoining these regions further regions that at least in some segments are substantially straight and that form yarn support regions for a plurality of loops of one yarn winding; the substantially straight region is followed by a radially protruding circular continuous yarn run-off rim of the drum body or of some part connected with it. The tapering regions and the substantially straight regions of all the yokes are each located on common imaginary rotational bodies that are coaxial with the drum shaft. Yarn delivery and run-off elements are associated with the storage drum on the yarn delivery and run-off side. A drive device is provided for attaining a relative rotation between the storage drum and the yarn delivery and run-off elements.
Various embodiments of yarn supply devices having a storage drum, typically rotatably supported on a holder, embodied in the manner of a cage with rods and having yarn support elements formed by straight cylindrical wires or thin rods secured at both ends in flange-like parts of a drum body disposed on the storage drum shaft are known, for example from German patent Disclosure Documents DE-OS No. 31 04 516 and 0E-OS No. 27 23 210. The yarn winding forming on the rods comes to have a polygonal shape corresponding to the number of rods, and this is advantageous for good slip-free yarn carriage, while on the other hand the relatively narrow yarn support faces formed by the rods provide favorable conditions for the axial feed of the storage winding. In order to effect this axial feed of the storage winding, however, it must be provided with its own feed devices, which are relatively expensive and complicated.
A yarn supply apparatus (German Patent Disclosure Document DE-OS No. 34 37 252 to which U.S. Pat. No. 4,669,677, Roser, corresponds of this type, belonging to the prior art, that dispenses with such feed devices, has its storage drum formed as a cage with rods, with yarn support elements in the form of yokes comprising thin spring wire, which are secured at both ends on the drum body and each of which, on the yarn delivery side, has a radially inwardly tapering region, which acts as a run-on incline for the oncoming yarn and which is followed by a substantially straight region which forms the yarn support region for a plurality of loops of the yarn or storage windings. Because of the incline of the run-on region, the loops of the incoming yarn that form here are automatically fed axially toward the yarn support region, under the influence of the yarn tension, so that a continuous feeding of the storage windings is attained.
From the storage windings, the yarn travels via the radially protruding circular run-off rim, which is continuous in the circumferential direction, to the yarn run-out eyelet. The arrangement is such that the yarn run-off rim is located on the drum body in the manner of a circular disk, the plane of symmetry of which extends approximately at right angles to the yarn support region of the yarn support elements. This arrangement is also basically applicable to the storage drums of the yarn supply apparatuses referred to at the outset above.
When certain yarns are processed, in particular polyamide or polyester yarns of lesser quality, torn-off individual filaments or other fiber parts can come loose from the yarn and become wrapped around the rods or around generally free-standing yarn support elements, especially in the yarn run-off region. Adhering accumulations of such yarn or filament particles can also form in the yarn run-off region between the rods or yarn support elements, and these accumulations increase over a relatively long period of operation. The final result of both phenomena is to prevent the proper run-off of yarn from the storage drum, causing disruptions in yarn supply.